What Does 1 Corinthians 14:13 Mean?

Wherefore let him that speaketh in an unknown tongue pray that he may interpret—Paul's practical command: the tongues-speaker should proseuchesthō hina diermēneuē (προσευχέσθω ἵνα διερμηνεύῃ, "pray that he might interpret"). This assumes (1) interpretation is a distinct gift from tongues, (2) it can be sought through prayer, (3) the same person can potentially exercise both gifts.

Paul doesn't say "stop speaking in tongues"; he says "pray for interpretation." This transforms tongues from self-edifying to church-edifying speech. The command places responsibility on the tongues-speaker: if you're going to exercise this gift publicly, ensure it edifies by seeking the interpretation gift. Love (chapter 13) compels this: don't settle for self-edification when you could serve the body.